Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2025
Erindi/veggspjald / Talk/poster V69
Höfundar / Authors: Emil Johnsen Loe, Arnar Ingi Vilhjálmsson, and Óttar Rolfsson
Starfsvettvangur / Affiliations: Department of Biochemistry and Molecular Biology, Medical School, University of Iceland.
Kynnir / Presenter: Emil Johnsen Loe
The endothelium plays a central role in vascular homeostasis and dysfunction during acute critical illness (ACU). Evidence indicates that shock-induced sympatho-adrenal activation is closely related with mortality in ACU. We previously found DIO2 to be upregulated in endothelial cells upon catecholamine stimulation. DIO2 encodes type II deiodinase, which converts thyroxine (T4) into triiodothyronine (T3). Variations in T3 levels are linked to poor outcomes in critically ill patients. We therefore hypothesize that DIO2 induction represents a key mediator of catecholamine–thyroid hormone crosstalk in the endothelium. We are currently validating a DIO2 knockout in the immortalized EA.hy926 cell line using CRISPR/Cas9. Genomic disruption has been confirmed by Sanger sequencing, resulting in a 74-aa truncated protein ending at residue 39. qPCR analysis shows that catecholamine-induced DIO2 upregulation is lowered in the KO clone compared to WT cells. Protein-level validation by immunoblotting provides partial confirmation of successful knockout. With this model, we will assess the functional role of DIO2 in adrenergic signaling under varying T4 conditions. We will quantify T4-to-T3 conversion, analyze metabolic alterations, and evaluate endothelial dysfunction through permeability assays. If successful, this work will clarify how endothelial DIO2 shapes catecholamine–thyroid hormone interactions and advance mechanistic understanding of vascular pathology in acute critical illness